Field of the Invention
This invention relates to the manufacture of stretch woven fabrics including staple corespun elastic yarn. It specifically relates to the fabrics and methods including a separated control yarn system within stretch fabrics.
Summary of Related Art
Stretch woven fabrics with staple core spun elastic yarn have been on the market for three decades. Textile manufacturers generally understand the importance of the right quality parameters to achieve fabrics acceptable to consumers. However, the industry is still looking for the way to produce stretch fabrics with better recovery power. A typical quality issue for current stretch fabrics is that fabrics failed to return to their original size after wearing, particularly for fabrics with a high stretch level. Consumers see “bagging and sagging” of the garment after long time wear. In these commercially available fabrics, the main body of the stretch fabric is formed only by one set of elastic corespun composite yarn. Elastic corespun yarn provides elasticity and stretch-recovery function to these fabrics.
Elastic core-spun yarns have a low modulus due to the inclusion of staple fiber in sheath and elastic fiber in core. The fabrics are easily extended during body movement, which provide comfort, fit and free movement benefit. However, when fabrics are over stretched out in some parts of the body, such as in knee, butt and waist, they can't quickly recovery to original size and shape. The garment shape and appearance are compromised by stretch function of the fabrics. The fabrics having improved recovery are still desired.
Most stretch woven fabrics are made with only one set of elastic yarns in the direction in which the stretch will exist. For example, corespun elastic yarns are commonly used as the filling yarn in order to make weft stretch fabrics. For stretch fabric, most elastic or elastomeric yarns are used in combination with relatively inelastic fibers, such as polyester, cotton, nylon, rayon or wool. However, for the purposes of this specification, such relatively inelastic fibers will be termed “hard” fibers.
U.S. Pat. No. 3,169,558 discloses a woven fabric with bare spandex in one direction and hard yarns in the other direction. However, the bare spandex must be draw twisted in a separate process, and spandex can be exposed on fabric surface.
Great Britain Patent GB 15123273 discloses a warp-stretch woven fabric and process where pairs of warp yarns, each pair having bare elastomeric fibers and a secondary hard yarn, are passed in parallel and at different tensions through the same heald eyelet and dent. This fabric also suffers from the deficiency of spandex being visible on the face and back of fabric.
Japanese Published Application No. 2002-013045 discloses a process used to manufacture a warp-stretch woven fabric using both composite and hard yarns in the warp. The composite yarn comprises polyurethane yarn wrapped with a synthetic multifilament hard yarn and then coated with size material. The construction of the composite is that of the composite yarns represented in FIG. 3A and FIG. 3B, before coating with size material. The composite yarn is used in the warp in various proportions to a separate synthetic multifilament hard yarn in order to achieve the desired properties of stretch in the warp direction. This composite yarn and method were developed to manufacture warp-stretch fabrics, and to avoid difficulties in the weaving of weft-stretch fabrics. However, the elastic yarns have the same size as hard yarn and exposed on the fabric surface.
U.S. Pat. No. 6,659,139 describes a way to reduce grin through of bare elastomeric yarn in warp direction of twill fabric. However, the elastomeric yarns are used in bare form and slippage of the elastomeric yarn occurs after the garment is washed. The workable fabric structure window is narrow and the weaving efficiency is low.
A stretch fabric with separated elastic yarn system is disclosed in U.S. Pat. No. 7,762,287, where a rigid yarn is used to form the main body of fabrics. Elastic composite yarns are hidden inside fabrics and provide the stretch and recovery.
In U.S. Pat. No. 8,093,160, a rigid control filament is combined with elastic filaments, as core the core of a spun yarn. A limitation of this approach is the on the ability of the control filament to limit growth due to the control filament being wrapped around the elastic filament with staple sheath surface fiber.